The beaver genus Castor is a large, primarily nocturnal , semiaquatic rodent. They are the second-largest rodent in the world after the capybara. This population decline is the result of extensive hunting for fur, for glands used as medicine and perfume, and because the beavers' harvesting of trees and flooding of waterways may interfere with other land uses. Although just two closely related species exist today, beavers have a long fossil history in the Northern Hemisphere beginning in the Eocene , and many species of giant beaver existed until quite recently, such as Trogontherium in Europe, and Castoroides in North America. Beavers are known for their natural trait of building dams on rivers and streams, and building their homes known as "lodges" in the resulting pond.
Busher, Peter E Informaition about beaver damns American beavers live throughout North America, but stay clear of deserts and the far northern areas of Canada. The Informaifion changes alter the type of invertebrates, and the new water source attracts new species of birds, fish and amphibians. Unsourced Cardiac nurse salary may be challenged and removed. International Journal for Parasitology.
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Research is sparse, but it seems likely that much of the fabled bottomland in North America was created, or at least added to, by the efforts of the generations of beavers that lived there. Veaver people are drawn to authority positions because they enjoy pushing other people around. The Department's dam concern that beaaver one or both of the dams Informaitikn during a recent rain event causing dam flooding is proof we should leave the dam Spring Pond Beavers Informaitioh rather than harassing them and calling them dam names. Besides silt, the beaver dam collects twigs and branches from the beavers' activity and leaves, notably in the fall. Wetlands also absorb large amounts of waterwhich counteracts the effects of heavy rainfall and can prevent potential floods. Southwestern Power Administration. In the Russian stocking teens century, the pope decreed that, due to Informaition about beaver damns scaly tail and semi-aquatic lifestyle, beaver could be considered a fish and be eaten during Catholic fasting days, according to ADW. Dear Mr. But, they are sometimes seen during the day. I know it is tough to fight city hall and was hoping to hear that you won the battle for Inofrmaition beavers! Beaver ponds can cause the removal of nutrients from the stream flow. The bull was gaining on the Water Rep with every step. Lodges are built on the banks of Informaition about beaver damns, on islands or on lake shores, just barely above water level. Beaver dams can be 10ft 3m high and up to 1,ft m long.
Aside from making cozy homes for their families and their friends, beavers play a leading role in nature's big picture when they build dams.
- Beaver dams or beaver impoundments are dams built by beavers to provide ponds as protection against predators such as coyotes, wolves, and bears, and to provide easy access to food during winter.
- Aside from making cozy homes for their families and their friends, beavers play a leading role in nature's big picture when they build dams.
- With a 6,acre lake, vibrant parks, wide array of visual and performing arts, numerous festivals, and plentiful healthcare options, quality of life is thriving.
Dams In areas where the natural water level is too low, beavers will construct a dam. They have even been known to incorperate beaver traps in the construction of their dams! The thickness of the dam is often around 5 ft. The length will depend on the stream width, but averages about 15 ft. In slow-moving water they may build a straight dam. Whereas in fast-moving water they tend to be curved. Branches and logs are then driven into the mud of the stream bed to form a base.
Then sticks, bark from deciduous trees , rocks, mud, grass, leaves, masses of plants, and anything else available, is used to build the superstructure.
A beaver dam. A common myth is that beavers use their tail to carry and pack mud between branches. Instead, beavers carry mud by holding it against their chest. A beaver can transport his own weight in material, and will drag the logs along mudslides and float them through canals to get them in place.
A beaver-chewed log. Image Source: Steve Hillebrand, U. Fish and Wildlife Service Available in two sizes: x x It takes a beaver about 20 minutes to cut down a 6 in. As the tree begins to fall, the beaver will run! If the dam breaks, they will rush around frantically to repair it.
If the they do not hurry, they could lose all of the water in their pond. This would expose the underwater lodge entrances to predators. Image Source: NPS Photo by Harlan Kredit Available in two sizes: x x A common myth is that beavers use their tail to carry and pack mud between branches. Fish and Wildlife Service Available in two sizes: x x It takes a beaver about 20 minutes to cut down a 6 in. LeFever, U. Fish and Wildlife Service. Image Source for two beaver at bottom of page: Tom Smylie, U.
It was the BEST! Their tails are narrower and skulls are smaller than those of the American beaver. Beaver Photo. Because of the dramatic effects their dams have on surrounding ecosystems, these mammals are considered a keystone species. Beaver create dams to make ponds, their favorite place to live. Science Daily. Somewhere along the way, the beavers were murdered.
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Two days later, General George Washington appointed the first Engineer. Ever since then, the Army Engineers have proudly answered the call to duty — in peace and war. Since the General Survey Act of , the US Army Corps of Engineers has played a vital role in the development and management of our national water resources. The Corps of Engineers has planned and executed major national programs for navigation, flood control, water supply, hydroelectric power, recreation and water conservation.
Beaver Lake was included in the comprehensive plan for flood control and other purposes in the White River Basin by the Flood Control Act of Construction began in and was completed in This cost was amortized over a year period, at an interest rate of payments to be accomplished annually from project revenue, which is derived primarily from hydropower sales.
Treasury general fund. Beaver Lake and Dam just celebrated our 50th Anniversary. Beaver Lake is one of five multi-purpose projects constructed in the White River Basin for the control of floods, generation of hydroelectric power, public water supply, and recreation. Beaver Lake is the first dam on the White River to provide a cold water fishery in the tail water. The blaring sounds of the warning horns at Beaver Dam signal that hydroelectric power is about to begin. Power generation at Beaver Lake is performed on an as-needed basis.
Peak times are generally in the early morning during winter months and mid-afternoons during summer. Be aware of suddenly rising waters and other hazardous water conditions below the dam and listen for the warning horns. A few things tell you a beaver is near. A stick-and-mud dam built across a stream at the edge of a lake can tell you a beaver is nearby. If you see stumps of small trees in the area showing tooth marks you will also know a beaver is nearby.
What they eat: Even though they have big front teeth, beavers only eat plants. Beavers like to eat a few different kinds of trees, including aspen, poplar, birch, maple, willow, and alder.
Beavers also eat bark and small twigs, and store small sections of logs underwater near I their lodge to eat later. But, they are sometimes seen during the day. Families of beavers, live together. In a family there are parents, yearlings big kids , and kits little kids. Beavers usually have one mate for life, just like people do! Once a beaver is two-years-old, it leaves the family. In beaver years, being two is a lot like being old enough to go to college.
Beaver | National Geographic
The beaver genus Castor is a large, primarily nocturnal , semiaquatic rodent. They are the second-largest rodent in the world after the capybara. This population decline is the result of extensive hunting for fur, for glands used as medicine and perfume, and because the beavers' harvesting of trees and flooding of waterways may interfere with other land uses.
Although just two closely related species exist today, beavers have a long fossil history in the Northern Hemisphere beginning in the Eocene , and many species of giant beaver existed until quite recently, such as Trogontherium in Europe, and Castoroides in North America.
Beavers are known for their natural trait of building dams on rivers and streams, and building their homes known as "lodges" in the resulting pond. Beavers also build canals to float building materials that are difficult to haul over land. In the absence of existing ponds, beavers must construct dams before building their lodges. First they place vertical poles, then fill between the poles with a crisscross of horizontally placed branches.
They fill in the gaps between the branches with a combination of weeds and mud until the dam impounds sufficient water to surround the lodge. They are known for their alarm signal: when startled or frightened, a swimming beaver will rapidly dive while forcefully slapping the water with its broad tail, audible over great distances above and below water. This serves as a warning to beavers in the area. Once a beaver has sounded the alarm, nearby beavers will dive and may not reemerge for some time.
Beavers are slow on land, but are good swimmers, and can stay under water for as long as 15 minutes. Beavers do not hibernate, but store sticks and logs in a pile in their ponds, eating the underbark. Some of the pile is generally above water and accumulates snow in the winter. This insulation of snow often keeps the water from freezing in and around the food pile, providing a location where beavers can breathe when outside their lodge.
Beavers have webbed hind-feet , and a broad, scaly tail. They have poor eyesight, but keen senses of hearing, smell, and touch. A beaver's teeth grow continuously so they will not be worn down by chewing on wood. The chisel-like ends of incisors are maintained by their self-sharpening wear pattern. Beavers continue to grow throughout their lives.
Females are as large as or larger than males of the same age, which is uncommon among mammals. Beavers live up to 24 years of age in the wild. The North American and Eurasian beavers are the only extant members of the family Castoridae , contained within the monotypic genus , Castor.
Genetic research has shown the modern European and North American beaver populations to be distinct species and that hybridization is unlikely. Although superficially similar to each other, there are several important differences between the two species. Eurasian beavers tend to be slightly larger, with larger, less rounded heads, longer, narrower muzzles, thinner, shorter and lighter underfur, narrower, less oval-shaped tails and shorter shin bones, making them less capable of bipedal locomotion than the North American species.
Eurasian beavers have longer nasal bones than their North American cousins, with the widest point being at the end of the snout for the former, and in the middle for the latter. The nasal opening for the Eurasian species is triangular, unlike that of the North American race, which is square.
The foramen magnum is rounded in the Eurasian beaver and triangular in the North American. The anal glands of the Eurasian beaver are larger and thin-walled with a large internal volume compared to that of the North American species.
The guard hairs of the Eurasian beaver have a longer hollow medulla at their tips. Fur colour is also different. The two species are not genetically compatible.
North American beavers have 40 chromosomes , while Eurasian beavers have These factors make interspecific breeding unlikely in areas where the two species' ranges overlap. The Eurasian beaver Castor fiber was hunted nearly to extinction in Europe, both for fur and for castoreum , a secretion from its scent gland believed to have medicinal properties.
However, the beaver is now being re-introduced throughout Europe. A thriving community lives in northeast Poland, and the Eurasian beaver also returned to the Morava River banks in Slovakia and the Czech Republic.
The beaver became extinct in Great Britain in the sixteenth century: Giraldus Cambrensis reported in Itinerarium ii.
In , Kent Wildlife Trust successfully introduced a family of beavers at Ham Fen, the last remaining ancient fenland in the county close to the town of Sandwich ; these are now established and are breeding. In October , six Eurasian beavers were reintroduced to Britain in Lower Mill Estate in Gloucestershire ; in July a colony of four Eurasian beavers was established at Martin Mere in Lancashire,  and a small population of probably Eurasian beavers is being monitored in Devon.
The North American beaver Castor canadensis , also called the Canadian beaver which is also the name of a subspecies , American beaver, or simply beaver in North America, is native to Canada, much of the United States and the states of Sonora and Chihuahua in northern Mexico.
The North American beavers prefer the inner bark of aspen and poplar but will also take birch, maple, willow, alder, black cherry, red oak, beech, ash, hornbeam and occasionally pine and spruce. These animals are often trapped for their fur. During the early 19th century, trapping eliminated this animal from large portions of its original range. Beaver furs were used to make clothing and top-hats. Much of the early exploration of North America was driven by the quest for this animal's fur.
The current beaver population has been estimated to be 10 to 15 million; one estimate claims there may have been at one time as many as 90 million. The primary habitat of the beaver is the riparian zone , inclusive of stream bed. The actions of beavers for hundreds of thousands of years  in the Northern Hemisphere have kept these watery systems healthy and in good repair. However, some beavers inhabit the intertidal zone in river estuaries, building dams to trap high tides in a beaver pond for similar purposes.
The beaver works as a keystone species in an ecosystem by creating wetlands that are used by many other species. Beavers fell trees for several reasons. Beavers fell small trees, especially young second-growth trees, for food. Broadleaved trees re-grow as a coppice , providing easy-to-reach stems and leaves for food in subsequent years. Ponds created by beavers can also kill some tree species by drowning, but this creates standing dead wood, which is very important for a wide range of animals and plants.
Beaver dams are created as a protection against predators, such as coyotes, wolves and bears, and to provide easy access to food during winter. Beavers always work at night and are prolific builders, carrying mud and stones with their fore-paws and timber between their teeth. Because of this, destroying a beaver dam without removing the beavers is difficult, especially if the dam is downstream of an active lodge. Beavers can rebuild such primary dams overnight, though they may not defend secondary dams as vigorously.
Beavers may create a series of dams along a river. The ponds created by well-maintained dams help isolate the beavers' homes, which are called lodges. These are created from severed branches and mud. The beavers cover their lodges late each autumn with fresh mud, which freezes when frosts arrive. The lodge has underwater entrances, which makes entry nearly impossible for any other animal, although muskrats have been seen living inside beaver lodges with the beavers who made them.
Beavers dig out their dens with underwater entrances after they finish building the dams and lodge structures. There are typically two dens within the lodge, one for drying off after exiting the water and another, drier one, in which the family lives. Beaver lodges are constructed with the same materials as the dams, with little order or regularity of structure. Usually, the dens have no connection with each other except by water.
When the ice breaks up in spring, beavers usually leave their lodges and roam until just before autumn, when they return to their old lodges and gather their winter stock of wood. They seldom begin to repair the lodges until the frost sets in, and rarely finish the outer coating until the cold becomes severe. When they erect a new lodge, they fell the wood early in summer but seldom begin building until nearly the end of August.
Beaver ponds, and the wetlands that succeed them, remove sediments and pollutants from waterways, including total suspended solids, total nitrogen, phosphates, carbon and silicates. The term "beaver fever" is a misnomer coined by the American press in the s, following findings that the parasite Giardia lamblia , which causes Giardiasis , is carried by beavers. However, further research has shown that many animals and birds carry this parasite, and the major source of water contamination is other humans.
Beaver populations in Canadian cities have seen a resurgence in numbers in the decades since the decline of the fur trade. Several cities in the United States have seen the reintroduction of beavers within their city limits.
Beavers were trapped to near extirpation and had not been seen in New York City since the early s. The " Lincoln Park beaver " has not been as well received by the Chicago Park District and the Lincoln Park Conservancy, which was concerned over damage to trees in the area.
In March , they hired an exterminator to remove a beaver family using live traps, and accidentally killed the mother when she got caught in a snare and drowned. When the city council wanted to remove the beavers because of fears of flooding, local residents organized to protect them, forming an organization called "Worth a Dam". In the s, beavers were brought from northern Manitoba in Canada to the island of Tierra Del Fuego in southern Chile and Argentina , for commercial fur production.
However, the project failed and the beavers, ten pairs, were released into the wild. Having no natural predators in their new environment, they quickly spread throughout the island, and to other islands in the region, reaching a number of , individuals within just 50 years. They are now considered a serious invasive species in the region, due to their massive destruction of forest trees, and efforts are being made for their eradication.
In contrast, areas with introduced beaver were associated with increased populations of native puye fish Galaxias maculatus , whereas the exotic brook trout Salvelinus fontinalis and rainbow trout Oncorhynchus mykiss had negative effects on native stream fishes in the Cape Horn Biosphere Reserve , Chile.
Beavers are classed as a "prohibited new organism" under New Zealand's Hazardous Substances and New Organisms Act , preventing them from legally being imported into the country. The basic units of beaver social organization are families consisting of an adult male and adult female in a monogamous pair and their kits and yearlings.
Beaver pairs mate for life; however, if a beaver's mate dies, it will partner with another one. Extra-pair copulations also occur. They also both mark and defend the territory and build and repair the dam and lodge. In the time after they leave the lodge for the first time, yearlings will help their parents build food caches in the fall and repair dams and lodges. Still, adults do the majority of the work and young beavers help their parents for reasons based on natural selection rather than kin selection.
They are dependent on them for food and for learning life skills. However, while copying behavior helps imprint life skills in young beavers, it is not necessarily immediately beneficial for parents as the young beaver do not perform the tasks as well as the parents. Older offspring, which are around two years old, may also live in families and help their parents.
In addition to helping build food caches and repairing the dam, two-year-olds will also help in feeding, grooming and guarding younger offspring. This behavior is common and is seen in many other animal species, such as the elephant and fathead minnow.